We propose to continue studying mechanisms by which oncogenic viruses induce transformation. These approaches include: identification of the Herpes Simplex virus genes responsible for induction and maintenance of transformation; studies of the mechanism of transformation of human lymphocytes by Epstein-Barr virus; investigation of the mechanisms which regulate transcription of the early region of SV40; and characterization of endogenous genetic information related to avian RNA tumor viruses in uninfected chicken cells.